全文获取类型
收费全文 | 34244篇 |
免费 | 3403篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 418篇 |
儿科学 | 1055篇 |
妇产科学 | 956篇 |
基础医学 | 4691篇 |
口腔科学 | 758篇 |
临床医学 | 3645篇 |
内科学 | 7128篇 |
皮肤病学 | 457篇 |
神经病学 | 2730篇 |
特种医学 | 1170篇 |
外国民族医学 | 9篇 |
外科学 | 4388篇 |
综合类 | 751篇 |
现状与发展 | 1篇 |
一般理论 | 28篇 |
预防医学 | 3948篇 |
眼科学 | 826篇 |
药学 | 2387篇 |
中国医学 | 37篇 |
肿瘤学 | 2312篇 |
出版年
2021年 | 460篇 |
2020年 | 268篇 |
2019年 | 460篇 |
2018年 | 531篇 |
2017年 | 469篇 |
2016年 | 442篇 |
2015年 | 461篇 |
2014年 | 733篇 |
2013年 | 1113篇 |
2012年 | 1561篇 |
2011年 | 1614篇 |
2010年 | 861篇 |
2009年 | 765篇 |
2008年 | 1422篇 |
2007年 | 1568篇 |
2006年 | 1511篇 |
2005年 | 1405篇 |
2004年 | 1280篇 |
2003年 | 1253篇 |
2002年 | 1274篇 |
2001年 | 1130篇 |
2000年 | 1179篇 |
1999年 | 991篇 |
1998年 | 365篇 |
1997年 | 327篇 |
1996年 | 352篇 |
1995年 | 313篇 |
1994年 | 326篇 |
1993年 | 300篇 |
1992年 | 922篇 |
1991年 | 912篇 |
1990年 | 824篇 |
1989年 | 775篇 |
1988年 | 682篇 |
1987年 | 699篇 |
1986年 | 696篇 |
1985年 | 679篇 |
1984年 | 559篇 |
1983年 | 433篇 |
1982年 | 335篇 |
1981年 | 286篇 |
1980年 | 260篇 |
1979年 | 531篇 |
1978年 | 324篇 |
1977年 | 260篇 |
1976年 | 279篇 |
1975年 | 319篇 |
1974年 | 353篇 |
1973年 | 293篇 |
1972年 | 273篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
82.
Platelet and whole blood serotonin content in depressed inpatients: correlations with acute and life-time psychopathology. 总被引:3,自引:0,他引:3
Platelet or whole blood serotonin content did not differ significantly in patients with major depression compared to healthy controls, but within the patient group, platelet serotonin levels correlated negatively with severity of depression (r = -0.49, p = 0.007). Levels were 39% lower in patients who had made a suicide attempt compared to nonattempter patients (47.2 +/- 27.3 versus 77.6 +/- 41.7 ng/10(8) platelets, p = 0.04). Conversely, comorbid borderline personality disorder (85.3 +/- 41.5 ng/10(8) platelets) was associated with 31% greater platelet serotonin content than nonborderline patients (58.9 +/- 31.1 ng/10(8) platelets) and 27% greater than healthy controls (62.4 +/- 19.8 ng/10(8) platelets). A pronounced seasonal variation in whole blood and platelet serotonin content was found in both patients and controls, largely due to lower levels in summer. Excluding cases tested in the summer abolished the statistically significant differences in patients with and without comorbid borderline personality disorder (BPD). Nevertheless, BPD attempters had lower serotonin levels than BPD nonattempters but higher serotonin levels than non-BPD attempters. Current hostility and a life-time history of aggression were positively correlated with platelet serotonin content (r = 0.44, p = 0.04 and r = 0.41, p = 0.06). This study provides evidence for an association between lower platelet serotonin content and depression and suicidal behavior, and association of higher platelet serotonin content and comorbid borderline personality disorder and behavior traits such as aggressivity. 相似文献
83.
84.
F Meneghini W A Rocca D W Anderson F Grigoletto L Morgante A Reggio G Savettieri R Di Perri 《Journal of clinical epidemiology》1992,45(4):319-331
In a hospital setting in Sicily, we assessed a screening instrument developed for a prevalence survey of parkinsonism, peripheral neuropathies, stroke, and epilepsy. The subjects consisted of (1) hospital patients with any of the above-mentioned diseases, to investigate sensitivity; and (2) hospital visitors free of all these diseases, to investigate specificity. The standard for comparison was a clinical evaluation based on specified criteria. Trained interviewers administered the screening instrument, asking subjects to answer symptom questions and to perform simple physical tasks. For the questions and tasks together, the sensitivity estimates were 100% for parkinsonism (n = 21), 96% for peripheral neuropathies (n = 22), 96% for stroke (n = 22), and 96% for epilepsy (n = 22), while the specificity estimate was 86% (n = 21). Analogous estimates were computed for the set of questions, for the set of tasks, and for each question and task individually. Despite limitations in our approach, we concluded that the screening instrument would be adequate for its intended use. 相似文献
85.
The purpose of this study was to determine the accuracy of FirstTemp (Intelligent Medical Systems, Carlsbad, CA) tympanic thermometer readings compared with core body temperatures obtained via pulmonary artery catheter (PAC). Five measurements were obtained on 19 cardiovascular surgery patients. Tympanic thermometer measurements tended to be higher than PAC measurements. However, most of the differences were not clinically significant. Differences found between right and left ear measurements were most likely due to poor measurement technique. When the correct technique is used, nurses can be confident that tympanic temperature readings are clinically accurate. 相似文献
86.
S Battersby B J Robertson T J Anderson R J King K McPherson 《British journal of cancer》1992,65(4):601-607
Steroid receptor was assessed immunohistochemically in 158 samples of normal breast for variation through the menstrual cycle. Patterns and intensity of reaction were used in a semi-quantitative scoring system to examine the influence of cycle phase, cycle type, parity and age. The changes in oestrogen receptor for natural cycle and oral contraceptive (OC) cycles indicated down-regulation by progestins. Progesterone receptor did not vary significantly in natural cycles, but increased steadily through OC cycles. This study provides strong evidence that both oestrogen and progesterone influence breast epithelium, but dissimilarities from the endometrium are apparent. The interval since pregnancy had a significant negative effect on frequency and score of oestrogen receptor and score of progesterone receptor. Multivariate analysis established the phase of cycle and OC use as independent significant influences on oestrogen receptor. The interval since pregnancy was an independent significant factor for both oestrogen and progesterone receptor presence. 相似文献
87.
88.
We conducted a study of the epidemiology of myasthenia gravis (MG) in four locations in central and western Virginia from 1970 through 1984. The population surveyed was 555,851 in 1984. A total of 73 new cases of MG occurred during the survey period, producing an overall average annual incidence rate of 9.1 per million. The point prevalence rate in 1980 was 13.4 per 100,000, and in 1984 it was 14.2. Approximately 15% of the population was black, and we found that incidence and prevalence rates for the black population were higher than the corresponding white population. When the population was subdivided into <50 and 50+ age groups, the incidence and prevalence were significantly higher in the older group. The rates we report here are higher than rates reported from any other locality. The reasons for the higher rates include optimal case identification, survey of a population with a higher incidence, and increasing aging of the population. 相似文献
89.
90.
Peter MA Calverley Romain A Pauwels Paul W Jones Julie A Anderson J?rgen Vestbo 《INT J CHRONIC OBSTR》2006,1(3):209-218
Guidelines recommend that patients with COPD are stratified arbitrarily by baseline severity (FEV1) to decide when to initiate combination treatment with a long-acting β2-agonist and an inhaled corticosteroid. Assessment of baseline FEV1 as a continuous variable may provide a more reliable prediction of treatment effects. Patients from a 1-year, parallel-group, randomized controlled trial comparing 50 μg salmeterol (Sal), 500 μg fluticasone propionate (FP), the combination (Sal/FP) and placebo, (bid), were categorized post hoc into FEV1 <50% and FEV1 ≥50% predicted subgroups (n=949/513 respectively). Treatment effects on clinical outcomes – lung function, exacerbations, health status, diary card symptoms, and adverse events – were investigated. Treatment responses based on a pre-specified analysis explored treatment differences by severity as a continuous variable. Lung function improved with active treatment irrespective of FEV1; Sal/FP had greatest effect. This improvement appeared additive in milder disease; synergistic in severe disease. Active therapy significantly reduced exacerbation rate in patients with FEV1 <50% predicted, not in milder disease. Health status and breathlessness improved with Sal/FP irrespective of baseline FEV1; adverse events were similar across subgroups. The spirometric response to Sal/FP varied with baseline FEV1, and clinical benefits were not restricted to patients with severe disease. These data have implications for COPD management decisions, suggesting that arbitrary stratifications of baseline severity are not necessarily indicative of treatment efficacy and that the benefits of assessing baseline severity as a continuous variable should be assessed in future trials. 相似文献